This invention generally relates to a method for programming a robot to follow a desired path. More particularly, this invention relates to a method of programming a robot to move a tool along a desired path using visual information to complete the programming process.
Industrial robots are increasingly being used for a wider variety of applications. In most instances, it is necessary to "teach" the robot the path along which the robot must move to complete the desired operation. For example, in a welding application, the robot must be programmed to move into a number of successive orientations that will effectively move the welding torch along the seam on the workpiece.
Programming or teaching a robot a desired path conventionally has been carried out manually. An operator interacts with the robot controller and manually causes the robot to move into the necessary orientations for placing the tool into the necessary positions along the desired path. Each of the positions is then programmed into the robot controller, which later repeats the programmed path. The process is typically time-consuming, difficult and often not accurate enough to yield satisfactory results at the end of the robot operation. Further, the conventional practice includes the drawback of having the operator within the robot work space during the teaching operation, which introduces the possibility for an undesirable collision between the robot and the operator.
Several systems have been proposed that include a robot vision system for controlling robot operation. None, however, have used the vision system to teach or program the robot to follow the program path. For example, U.S. Pat. Nos. 4,616,121; 4,965,499; and 5,572,103 each include a vision system associated with an industrial robot that provides visual information for making corrections to a preprogrammed path during robot operation. Such systems have been proposed for accommodating deviations between an actual desired path and a preprogrammed path that the robot is following. In each of these systems, however, it is necessary to preprogram the robot in the conventional manner.
There is a need to simplify and improve current robot path teaching methods. For example, it is desirable to eliminate the need for the operator to be within the robot work envelope during the path training procedure. Additionally, it is desirable to improve efficiency in teaching a robot path by reducing the amount of time required.
This invention addresses the needs described above while avoiding the shortcomings and drawbacks of the prior art. This invention provides a method of automatically teaching a robot path using visually acquired information regarding the desired path.